In this exercise you should utilize the iso_fortran_env intrinsic
module.
Start from your own solution to Finite-difference Laplacian exercise or the provided skeleton code laplacian.F90.
Declare all floating point numbers with double precision (64 bit)
precision. It is recommend to define the precision in a separete
module which you use in the main program.
In the main program, also write out the compiler command and compiler options.